This invention relates to a rod brake. Rod brakes, frequently used on pneumatic or hydraulic cylinders are more properly rod locks. That is, they are used for the locking of a stopped shaft. In emergency cases, the rod brakes can be used to stop a moving shaft. However, there is a risk of damage to the brake and to the shaft. There are two common types of rod locks. First is a collet lock. In a collet lock, a collet, through which the shaft passes, squeezes on the shaft through means of tapered balls, wedges or mechanical levers. The second type is a pivot or swash plate design. In this design, the rod or shaft passes through a hole in an eccentrically mounted plate. Spring action and motion of the rod causes the plate to twist and bind on the shaft. This type of brake typically operates only in one direction. Further, neither type of brakes of the prior art is suitable for stopping rotational motion of the rod. In addition, both brakes require hardened or high strength steel shafts which adds increased costs to the entire system.